Gonna Reinstall My Skeg/Rudder Flaps At Next Month' Haulout

[DianaOfBurlington]

Rardi--

I am thinking that a strip of copper, properly treated and coated in Interprotect, fastened to the skeg, would be the traditional and most durable way to go. Any plastic, buried underwater, will go brittle and chip, crack, bend, etc. But yachts and ships have used copper sheet for years. (Just mind what sort of bottom paint you use on it!)

BUT, before you do this, measure your best hull speed under power, in flat conditions, at a given RPM. Also see how the boat tracks, heeled, when you let go the helm. Then, given the chance, take off the banal plastic things and take the same measurements. I'm sure you suspect what I'm suspecting by now.

 

[rardiH36]

Blaise - Thanks for the expanded description. Any idea in the thickness of the Mylar core? Is it Mylar "sail cloth"? How many layers? I've got my own sewing machine to put at risk! An old Kenmore with 100 pct metal gears. 'Bout five layers sail cloth it it's Max.

John - No I am not expecting to notice a difference. And at $450 for in/out, it would an expensive experiment. I am only hoping that properly functioning flaps might give that say 1/10th knot average speed improvement or that 0.5 degree better pointing ability to get me across the bay 50 yards further upwind 10 seconds sooner. Of course I would never be able to discern the subtle difference.

 

[Blaise]

Re: Gonna Reinstall My Skeg/Rudder Flaps At Next Month' Haul

Rardi,
I don't know the thickness of the mylar, The two layers of 10oz cloth were equally stiff. Can't comment on the exact speed difference. I do know that taking part in a sport where people will spend thousands for a tenth on a knot increase, this was a lot of bang for the buck. They at least reduce the turbulance noise a lot when you tack.

 

[rardiH36]

Re: Gonna Reinstall My Skeg/Rudder Flaps At Next Month' Haul

Blaise:

Thanks the additional description. I decided to go with what has worked for you. Today I visited TAP plastics and bought 4 ft2 of mid thick mylar plastic sheeting. I'll use two layers inside with thick dacron sail cloth on the outside stitched around the perimeter and also across the "field" area. Then I will paint both sides with the same modified epoxy bottom paint I will be using for the rest of my hull. I have noticed that the tell-tale window on one of my jibs has similar feeling plastic as the mylar I bought. So makes sense that it's window plastic that the sail maker uses for you.

And Alctel -- Thanks for the dimension information.

rardi

 

[DianaOfBurlington]

Blaise raises a good point: plastic might be the thing here. I would suggest some slender Delrin; but know that this will, in time, be eaten away underwater. Delrin isn't cheap-- but, saving the patterns, you'll be able to remake these every 7-8 years or so.

 

[Alctel]

Blaise:

Thanks the additional description. I decided to go with what has worked for you. Today I visited TAP plastics and bought 4 ft2 of mid thick mylar plastic sheeting. I'll use two layers inside with thick dacron sail cloth on the outside stitched around the perimeter and also across the "field" area. Then I will paint both sides with the same modified epoxy bottom paint I will be using for the rest of my hull. I have noticed that the tell-tale window on one of my jibs has similar feeling plastic as the mylar I bought. So makes sense that it's window plastic that the sail maker uses for you.

And Alctel -- Thanks for the dimension information.

rardi

No worries, I'm glad to be able to help for once instead of the one asking questions